Servo-mechanism



June 25, 1935. H, C, EDWARDS 2,005,971 sERvo MECHANISM i Original Filed March 31, 1932 2 Sheets-Sheet l June 25, 1935; H, Q EDWARDS 12,005,971

SERVO MECHANI SM original Filed March 31', 1932 2 sheets-sheet 2 Patented June 25, 1935 UNITED STATES PATENT f OFFICE SERVO-MECHANISM Original application March 131, 1932, Serial No. 602,233. Divided and this application August 7, 1933, Serial No. 683,976

9 Claims.

This invention relates to control mechanism and more particularly to mechanism of the servo type, this application being a division of my ap plication Serial No. 602,233, led March 31, 1932.

An object of this invention is to provide a new and novel form of servo-mechanism which is sensitive and manually controllable within small limits of movement.

Another object of the invention is to provide a control mechanism in which hydraulic servomechanism can be selectively connected or disconnected so that either manual or hydraulic means can be employed to actuate the same.

A further object of the invention is to provide an improved form of hydraulic control mechanism.

Other objects of the invention will appear from the following description taken in connection with the drawings, which form a part oi this specification, and in which:

Fig. 1 is a sectional view of a device incorporating the invention;

Fig. '2 is a sectional view through the servomechanism taken on line 2 2 of Fig. 1;

Fig. 3 is another sectional View of the servomechanism taken on line 3-3 of Fig. 1;

Fig. 4 is still another sectional view of the servo-mechanism taken on line 4 4 of Fig. 1;

Fig. 5 is an elevational view of the device;

Figj is a sectional view of the device taken on line E-$ of Fig. l;

Fig. '7 is a longitudinal section of the plunger forming a part of the servo-device taken on line 1-1 of Fig. 3;

Fig. 8 is another longitudinal section of the plunger of the servo-device taken on line 8-8 of Fig. 3;

Fig. 9 is a sectional view of a fragment of the servo-device taken on line 9-9 of Fig. 5;

, Fig. 10 is a plan View, partly in section, of the control means for the servo-mechanism and one of the actuators operated thereby;

Referring now to the drawings by characters of reference, 66 represents an actuator element, for adjusting mechanism to regulate fuel injections for engines, upon which Ais iixed a rack member 10 which meshes with a gear segment xed on a yoke 1i mounted on a shaft 12. 30 represents another actuator for adjusting mechanism to regulate air supplied to engines and between such actuators I provide connecting means so that they can be operated by mechanism of the servo type which is manually controlled.

The servo-mechanism is mounted upon a support B5 and is connected with a source of uid under pressure. A housing or cylinder 80 is secured to the support 65 and is provided with an oil inlet port 8i which is connected with a pressure system by means of a conduit 82 provided in the bracket 83. I'he engine lubricating system is arranged to lead into the passage 84 in the support, for example, as shown in the application of Lionel M. Woolson, filed April 4, 1930, Serial No. 441,390, and an outlet 85 is provided in the cylinder through which oil returns to the lubricating system.

Within the cylinder is arranged a plunger element consisting of a central body portion 86 and two end portions 81 and 88, the end portion 88 being .formed with a sleeve 89 which extends through the bearing 90 at one end of the cylinder.' Another sleeve 9i is arranged to telescope into the sleeve 89 and threaded therein is a shaft 92 which extends in'to the cylinder and through the piston stucture. The other end of this shaft 92 has an vextension 93, detachably secured therewith, which is arranged to slide through a bearing 94 formed on one end of the cylinder. Within the last mentioned bearing is a packing ring 95 which is compressed by a nut 96 screwed into the end of the bearing, such nut being hollow so that the shaft extension 93 can slide therein. The purpose of the shaft extension 93 and its arrangement with the packing is to provide resistance to free movement of the shaft 92 in the cylinder. The'piston sections are secured together by a plurality of axially extending bolts, as indicated at 91. Each end of the central section 86 of the piston structure is formed with a pair of separate chambers which extend in a plane transversely to the piston axis, one of the chambers 98 at each end of the piston serves as an inlet while the other chamber 99, at each end of the piston,'serves as an outlet. Extending in an axial direction through each of the end sections of the piston is a port |00 which is arranged to establish open communication between the outlet chamber 99 and the end of the cylinder.

The piston end sections are also provided with suitable rings, as indicated at |02, to prevent leakage around the cylinder engaging portion thereof. The central section of the piston structure is formed with a pair of saw-cuts forming chambers |03 which extend into the periphery a short distance in Aspaced relation axially and which slightly overlie each other axially of the piston so that they each communicate with a longitudinally extending recess iM formed in the central 'piston section and extending axially thereof, this recess being arranged so that it communicates with the outlet port 85 in the cylinder and chambers |03 being arranged so that they each communicate with an outlet chamber 99. The central portion of the piston is also formed with a similar pair of saw-cuts in the periphery thereof, opposite the saw-cuts |03, forming chambers |05 which are in spaced relation axially of the piston and in open communication with a recess |05 which extends in an axial direction along the periphery of the central section of the piston. The recess |06 is arranged to register with the inlet port 8| in thecylinder, and the chambers |05 are in open communication with the chambers 98.

Valves, as indicated at |06', are arranged to co-operate with seats |01 in order to control the passage of fluid between the chambers 90 and |08, such valves extending in opposite directions. Another pair of valves |08 are arranged to cooperate with seats |09 formed in the central piston section in order to control flow of fluidk between the outlet chambers |03 and 99.

The Valve position is controlled by the rod 02 and on such rod I provide arms and l which are located in recesses formed in the piston so that they can reciprocate with the shaft 82. The arm ||0 is provided with adjustable tappets i2 which are arranged to align with the ends of the pair of valves associated with the oppositeV end of the piston and the arm carries adjustable tappets I3 which are arranged to align with the valve ends |08 and |06 for the other end of the piston structure. Surrounding each of the valve stem ends is a coil spring H4 which seats at one end against the piston and at the other end engages a retainer H5 fixed adjacent the end of each of the stems, such springs normally tending to move the valves intoa closed position with their seats. The tappets are set close to the valve ends so that a very short movement ofthe rod and arms is required in order to open the valves. In order that the rod 9| can be actuated to move the piston structure manually, I provide shoulders ||6 with which the arms lll'and H2 engage upon a short movement of the rod 9|.

The outlet chamber 99 at each end of the piston structure communicates with the inlet cham'- ber at the opposite end of the piston structure through means of axially extending passages ||1 extending through the central' piston section and surrounding two of the bolts 81. f

A bearing extends through the crank case r l0 and is clamped to the crank case by a nut 2 I.

Projecting through the bearing is a sleeve |22 and carried by the sleeve is the shaft 12. To the outer end of the shaft is fixed an arm |24 having an end |25 to which suitable mechanism, as indicated at |25', can be fixed for rotatingthe' arm from a remote location. Both the shaft 12 and the sleeve' |22 are freely rotatable relatively, and relative to the bearing |20. The yoke member 1| is formed at one end with tongues |26 which extend into complementary recesses in the inner end of the sleeve |22.

The shaft 92 is threaded into the sleeve 9| and projects beyond the end thereof, such sleeve being also telescoped within the sleeve 89 and projecting beyond its end. A pin |21 extends through the projecting end of the sleeve 9| and pivotally mounted on such pin is a link |28. The other end of this link extends between the arms of a yoke |29, which is pressed onto the end of shaft '12, and the link |28 and yoke |29 are pivotally connected by the pin |30. The arms of the yoke 1| have pivot members |8| extending therethrough and pivotally mounted on such pivot members is a U-shaped link |32. Threaded upon the projecting end of the sleeve 89 is an extension |33 pivoted on the pins |3| carried by one end of the sides of the link |32. The other end of the sides of the arms of the link |32 are mounted upon pins |35 which are fixed to arms |30 projecting from the gear segment yoke 1 The arm |20 is arranged with relation to the engine so that the forward or rearward movement of the extended operating mechanism associated therewith will cause rotation of the shaft 12. Such movement of the shaft 12 will rotate therewith the yoke |29 which in turn will impart movement to the link |28 which is transmitted through the pin |21 toI reciprocate the sleeve 9|, and as this sleeve is iixed to the shaft 92, the arms l I0 and I|| will be moved in an axial direction in the cylinder 80.

When the shaft Sii-is moved toward the bottom end of the cylinder, as shown in Figs. 1 and 6, the tappets H2 on the arm H0 will engage the stem ends of the valves |00 and |08 at the upper end of the piston and will move them toward the bottom end of the cylinder establishing communication between the lower inlet chamber |05 and port 8| in the cylinder, the open inlet chamber |05 andinto the chamber 93. Such oil flow passes from the chamber 98 axially of the piston through the port ||1 and into the upper exhaust chamber 99 from which it flows through the port |00 `into the upper end of the cylinder and thereby exerts a downward pressure against the piston causing it to move with the rod 9| toward the bottom of the cylinder. While the lower inlet valve |00. is thus held open, the outlet valve at the lower end of the piston is also; held open and fluid in the bottom end of the cylinder can iiow through the port |08 and the outlet chambers 98 and |03 and thence intel the recess |00 and through the outlet port 85 in the cylinder. The outlet port 85 opens directly intoy the crank case and the oil dro-ps to the bottom thereof along with that which has escaped from the bearings 'within the crank case and is recirculated in the system in the usual manner. The port 8| is always in open communication with the system through conduit means previously described so that whenever either one of the inlet valves |053 4is open, oil from the system is free to flow into one or the other end of the cylinder because the inlet passages |05 are always in. communication with the port 8| through the axially extending recess |00 formed in the periphery of the piston. The exhaust port 85 is always in open communication with the outlet chambers |03 even though they are in different axial planes for the reason that there is a space between the cylinder wall and the-chambers |03 formed by the recess |04 and whenever the valves |08 are open, there will be a flow from one end or the other of the cylinder'through the port 85.

Upward movement of the shaft 02 will open the valves at the upper end of the piston and similar flow of iiuid will pass through the cylinder and the piston structure in a similar but reverse manner as that just previously described. In this manner, rotation of the shaft 12 will take only suiiicient energy to move the arms 0 or into a relation opening the adjacent valves, whereupon there will be a corresponding movement of the piston efectedby the system so that very little'manual effort is required in order to move the piston within the cylinder. Friction of the bearing member against the shaft extension 93 is sufficient to keep the regulating mechanism in a denite relation with the servo device, `thus preventing creeping of the members 30 and 66 in any adjusted position due to engine vibration. The tappets |2 and 3 are adjusted so that very little movement of the bars |||l and is required in order to open the associated valves which also tends to decrease the amount of manual effort required before the hydraulic or servoaction takes place. v

When starting the engine, there is of course no pressure in the system and hand operation of the mechanism is resisted by the high vacuum in the cylinder. In order to overcome this resistance to manual operation `of the mechanism, I provide the passage |40 which extends substantially normal to and in communication with the passage 82 in the supporting bracket 83, and into the outer end of this passage |40 I provide an air inlet cap |4|. A one Way ball valve |42 is arranged within the inlet memberV |4| and is normally held to close the port |43 by means of a spring |44. When there is pressure in the passage 82, it will maintain the valve |42 in closed position so that there can be no entrance of air, but when there is a vacuum in the cylinder, then air is free to flow into the cylinder and thereby reduces the'vacuum so that vacuum resistance to manual operation is substantially reduced. 4

As the sleeve 89 is formed as an integral part of an end section of the piston, it will reciprocate with the piston and in so doing will impart similar movement to the yokeY extension |33 and through means of the pins |3|, this motion being transmitted to the link |32 which transmits rotation to the gear segment yoke 1| through the pin connections E35. Rotation of the gear yoke is imparted to the rack 10 which is xed to the ring 66 and is also imparted to the sleeve |22 through means of the association of tongues |26 with the recesses in the sleeve.

"It will thus be seen that the sleeve |22 and the ring 66 are both responsive to reciprocatory movement of the piston. Occasionally it is desirable to move the actuator 66 faster than the servo-mechanism will operate. and, under such circumstances, the fast movement of the rod 92 will cause the one or the other" of the arms ||0 or to engage against the adjacent shoulder |||i formed of the piston structure, depending upon the direction of the shaft movement, and such engagement will allow the piston to be moved manually as quickly as may be desired. It will therefore be seen that, in case of emergency or when desired, adjustment of the'actuators 56 and 3l! can be made manually. The sleeve |22 is rotated withthe gear segment yoke 1| and carriedby the outer end of the sleeve is a roller |45 which is located to engage in a recess |43 formed in an arm |47 fixed to a rotatable support E. An arm 32 is fixed on the rotatable sleeve 20 and has a ball shaped end |49 engaging in a socket formed in an arm 3| on a. hub 33 which is fixed to the actuator 3|). It will therefore be seen that rotation of the sleeve |22 will rock the rollerl |45 which engages with the arm |41 and rotates the associated support 2l) so that the arm 32 associated therewith will move the actuator 30. Thus rotation of the gear yoke and the sleeve |22 occur simultaneously so that the actuators 66 and 30 Will be moved together.

The control mechanism described is compact and sensitive and can be actuated manually or hydraulically at will.

Although the invention has been described in connection with a specific embodiment, the principles involved are susceptible of numerous other applications which will readily occur to persons skilled in the art. The invention is therefore to be limited only as indicated by the scope of the appended claims.

What I claim is:

l. In a servo-mechanism, a cylinder having fluid inlet and outlet ports in the wall'thereof, a piston in the cylinder composed of three axially arranged sections having bolts for securing the same together, the central section of the piston having an enlarged passage around two of the bolts, a pair of peripheral recesses extending the length of the central section and communicating one with the cylinder inlet port and the other with the cylinder outlet port, a pair of chambers extending normal to the axis of the central piston portion through each recessed portion of the outlet recess periphery, axially extending openings in each of the end piston sections each communicating with one of the chambers communicating with the valve means in the piston controlling the passage of uid between the outlet chambers and the openings in the end sections, manuallyoperable means for controlling the position of the valve means, the chambers communicating with the inlet recess each-being in communication with the openings in the remote end sections through means of the enlarged passages around the bolts, and actuator means connected with thepiston and extending exteriorly of the cylinder.

2. In a servo-mechanism, a cylinder having iluid inlet and outlet ports in the peripheral Wall thereof, a piston in the cylinder, the central portion of the. piston having two axially extending passages therein, a pair of peripheral recesses extending axially of the central portion of the piston and in open communication one with the cylinder inlet port and the other with the cylinder outlet port, axially spaced pairs of chambers extending transversely in the piston and communicating with the peripheral recesses, axially extending openings in eachend of the piston communicating with the chambers, valve means in the piston controlling the passage of fluid between the chambers and the openings in the end portions of the piston, manually operable means for controlling the position of the valve means, the chambers communicating with the inlet recess in the piston each being in communication with the openings in the remote end portion of the piston through means of the axial passages in the central portion of the piston, and actuator means connected with the piston and extending exteriorly of the cylinder.

3. A servo-mechanism comprising a cylinder having iluid inlet and outlet openings through the peripheral Wall thereof, a piston reciprocable in the cylinder having a peripheral recess communicating with the inlet opening and another` peripheral recess communicating with the outlet opening, a pair of chambers extending in a transverse plane adjacent each end of and within the piston, one of each pair of chambers com- Vmunicating with one piston recess and the other of each pair of chambers communicating with of the chambers at each end of the piston with the inlet opening and the other chamber at each end of the piston with the outlet opening, valve means for closing the junctions between the chambers and the passages, axially extending openings connecting the inlet chambers with the outlet chambers, axial passages leading from the chambers through the adjacent head ends of the piston, manually operable means extending into the cylinder for regulating the position of the valves, and actuator means connected with the piston and extending axially of the cylinder.

4. A servo-mechanism comprising a cylinder having iiuid inlet and outlet openings through its peripheral wall; a piston in the cylinder formed of three aligned sections, said middle section having peripheral recesses communicating with the inlet and outlet openings, a pair of transversely extending chambers in each end, connecting passages between a chamber at each end and the inlet recess and between the other chamber at each end and the outlet recess, connecting passages between the inlet and outlet chambers at opposite ends of the section, said piston end sections having axially extending openings therethrough communicating one with each adjacent chamber; valve means normally closing the chambers from the connecting passages; manually operable means for opening said valves; and actuator means connected to be operated by the piston,

5. A servo-mechanism comprising a cylinder having fluid inlet and outlet openings through the peripheral wall thereof, a piston reciprocable in the cylinder having a pair of peripheral recesses one communicating with the inlet openings and the other communicating with the outlet openings, a pair of chambers in the piston adjacent each end thereof, one chamber of each pair communicating with the inlet recess and the other chambers communicating with the outlet recess, passages connecting one of the chambers at each end of the piston with the inlet opening and the other chamber at each end of the piston with the outlet opening, Valve means normally closing the junctions between the chambers and the passages, axially extending openings connecting the inlet chambers at one end with the outlet chambers at the other end ofthe piston, axially extending passages leading from the chambers through the adjacent head end of the piston, manually operable means extending into the cylinder for selectively opening the valves at either end thereof and actuator means connected with the piston and extending exteriorly of the cylinder.

6. A servo-mechanism comprising a cylinder having uid inlet and outlet openings through the peripheral wall thereof; a piston in the cylinder, an intermediate portion of said piston having peripheral recesses communicating with the inlet and outlet openings, a pair of transversely extending chambers in each end, connecting passages between a chamber at each end and the inlet recess and between the other chamber at each end and the outlet recess, and connecting passages between the inlet and outlet chambers at opposite ends of the piston, the end portions of said piston having axially extending openings therethrough communicating one with each chamber; spring seated valve means in the piston normally closing each chamber from the passage connected therewith; a manually operable rod extending into the piston and having a pair of arms iixed thereon for selective opening engagement with the valves at either end of the piston; and actuator means connected to be operated by the piston.

7. A servo-mechanism comprising a cylinder having fluid inlet and outlet openings through the peripheral wall, a piston reciprocable in the cylinder having peripheral recesses communicating'one with the inlet opening and the other with the outlet opening, a pair of chambers adjacent each end of and within the piston, passages connecting one of the chambers at each end of the piston with the inlet opening through the recess communicating therewith and the other at each end of the piston with the outlet opening through the recess communicating therewith, spring seated valves for closing the junctions between the chambers and the passages, axially extending openings in the piston connecting the inlet chambers at one end with the outlet chambers at the other end, axially extending passages extending from the chambers through the ends of the piston, a manually operable rod extending through the piston and having a pair of spaced arms xed thereon for engaging the valves at either end of the piston to selectively unseat them, said arms abutting said piston after a predetermined movement relative thereto to manually operate the saine, and actuator means connected with the piston and extending exteriorly of the cylinder.

8.` A servo-mechanism comprising a cylinder having uid inlet opening and a fluid outlet opening through the peripheral wall thereof, a piston reciprocable in the cylinder having a peripheral recess communicating with the inlet openingand another peripheral recess communicating with the outlet opening, a pair of cham- -bers within the piston adjacent each end thereof, passages connecting one of the chambers at each end of the piston with the inlet opening through the peripheral recess associated therewith and passages connecting the other chambers at each end of the piston with the outlet opening through the peripheral recess associated therewith, spring seated valves for closing the junctions between the chambers and the passages, axially extending openings connecting the inletchambers with the outlet chambers, axially extending passages leading from the chambers through the ends of the piston, manually operable means extending through the piston for selectively operating the valves at either end thereof, said means after a limited movement relative to the piston engaging therewith tocause manual operation thereof, and actuator means connected with the piston and extending exteriorly of the cylinder.

9. A servo-mechanism comprising a cylinder having fluid inlet and outlet openings through the peripheral wall thereof, a piston reciprocable in the cylinder having a peripheral recess communicating with the inlet opening and another peripheral recess communicating with the out-I let opening, a pair of chambers in the piston adjacent each end thereof, passages connecting one of the chambers at each end of the piston with the inlet opening through the recess associated therewith and the other passage at each end of the piston with the outlet opening through the recess associated therewith, spring seated valves for closing the junctions between the chambers and the passages, axially extending openings connecting the inlet chambers with the outlet chambers at opposite ends of the piston, axially extending Dassages leading from the chambers through the ends of the piston, inwardly opening spring seated valve means associated with the inlet opening in the cylinder through which air automatically passes upon a drop of pressure below atmospheric in the cylinder, manually operable means extending into the cylinder for selectively opening the valves at either end of the piston, and actuator means connected with the piston and extending exteriorly of the cylinder.

CERTIFICATE OF CGRRECTION.

Patent No. 2,005,971. June 25. 1935.

HERBERT C. EDWARDS.

it is hereby eerted tmt error appears n fzhe printed specieatioe of the above numbered patent requiring cerrecion as fellows: Page 3, second enlumn, line 26, claim 1, srike our the words "outlet recess" and insert the seme before "valve" n line 29, of said claim; and tha the said Letters Patr-mf; shouid be read with this correction therein ihm the same may conform te the recerr of the ease in the Patent Office.

Signed and sealed this th day ef August, A.. D. E935.

Leslie Frazer (Serri) Acting Gemmssener of Patents. 

